Hydraulically driven diaphragm pump with a magnetic coupled diaphragm assembly

ABSTRACT

characterized in that the diaphragm stop element has a recess, into which the tie rod and/or the magnet connected to the tie rod is inserted, so that the diaphragm assembly is centred with respect to the tie rod.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application having serial number 10 2019 128 059.1, filed on Oct. 17, 2019. The entirety of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments of the present invention relate to a hydraulically driven diaphragm pump having a magnetically coupled diaphragm assembly.

SUMMARY

A diaphragm pump and methods for using same are provided. The pump can include a diaphragm assembly comprising a diaphragm, a diaphragm stop device fixing the diaphragm, and a diaphragm return device comprising a tie rod. The diaphragm assembly and the tie rod can be connected to each other with a magnetic adhesive force, wherein a first magnet for providing the magnetic adhesive force is arranged on or in the area of the tie rod. The diaphragm stop device can have a recess into which the tie rod and/or the first magnet connected to the tie rod can be inserted, so that the diaphragm assembly is centred with respect to the tie rod.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments. It is emphasized that the figures are not necessarily to scale and certain features and certain views of the figures can be shown exaggerated in scale or in schematic for clarity and/or conciseness.

FIG. 1 shows a detail of a first embodiment of a diaphragm pump in a lateral sectional view having a magnet arranged on the tie rod according to at least one embodiment of the invention;

FIG. 2 shows a detail of a second embodiment of a diaphragm pump in a lateral sectional view having a spherical centring support according to at least one other embodiment of the invention;

FIG. 3 shows a detail of a third embodiment of a diaphragm pump in a lateral sectional view, having a trapezoidal centring support according to at least one other embodiment of the invention; and

FIG. 4 shows a detail of a fourth embodiment of a diaphragm pump in a lateral sectional view having recesses on the diaphragm stop element and tie rod, the depth of the recess of the diaphragm stop element being greater the height of that part of the first magnet which is connected to the tie rod and which is inserted into the recess, according to at least one other embodiment of the invention.

DETAILED DESCRIPTION

A diaphragm pump can include a delivery chamber with a suction connection and a pressure connection. Diaphragm pumps also have a working chamber that is separated from the delivery chamber by a diaphragm. To deliver a fluid or other medium, the diaphragm is moved to and from in an oscillatory manner between a first and second position, in which the working chamber is filled with a hydraulic fluid to which an oscillating pressure is applied. The two positions of the diaphragm are normally designated as the pressure stroke position and the suction stroke position.

The pressure connection can be connected to the delivery chamber via a pressure valve formed as a non-return valve, and the suction connection can be connected to the delivery chamber via a suction valve likewise formed as a non-return valve. During the movement of the diaphragm from the first into the second position, the so-called suction stroke, the volume of the delivery chamber can be enlarged, as a result of which the pressure in the delivery chamber drops. As soon as the pressure in the delivery chamber falls below the pressure in the suction line connected to the suction connection, the suction valve opens and medium to be delivered can be sucked into the delivery chamber via the suction connection. As soon as the diaphragm moves from the second position in the direction of the first position again (this is the so-called pressure stroke), the volume in the delivery chamber decreases and the pressure in the delivery chamber rises. The suction valve can be closed in order to prevent the medium to be delivered from flowing back into the suction line. As soon as the pressure in the delivery chamber exceeds the pressure in a pressure line connected to the pressure connection, the pressure valve can be opened, so that the medium to be delivered which is in the delivery chamber can be forced into the pressure line.

The diaphragm itself can be spring-preloaded in the direction of the suction stroke position. The diaphragm can assume a position in which the forces acting on the diaphragm cancel one another. Under normal conditions, the forces generated by the fluid pressure in the delivery chamber and those generated by the spring preloading in the direction of the suction stroke position act counter to the forces generated by the fluid pressure in the working chamber.

Applying an oscillating pressure to the hydraulic fluid thus leads to an oscillatory movement of the diaphragm and, connected thereto, to an oscillatory pumping operation of the fluid to be delivered out of the suction line into the pressure line.

Hydraulically operated diaphragm pumps are preferably used during the delivery of fluids to be delivered under high pressures, since the hydraulic fluid loads the diaphragm uniformly and the latter thus has a long service life.

As explained, the diaphragm co-operates with a diaphragm return device, normally comprising a tie rod, which acts in the direction of the suction stroke position. To this end, the diaphragm must be connected directly or indirectly to the tie rod in order that the tie rod can act on the diaphragm.

The diaphragm can include multiple layers, normally two polytetrafluoroethylene (PTFE) layers which enclose a fabric layer in a sandwich construction. The diaphragm assembly can be formed together with a diaphragm stop disc and a clamping screw, which in turn fix the aforementioned layers.

To connect the diaphragm assembly to the tie rod, various solutions are known and described in the prior art. For example, the diaphragm assembly has a threaded extension, which can be screwed into the tie rod as far as a fixed stop. A key prevents co-rotation of the tie rods. The disadvantage with this solution is that a thread may be broken in the event of improper installation. Furthermore, it is disadvantageous that recourse has to be had to a specific tool and the diaphragm itself can be damaged during the assembly by means of this tool. Furthermore, it is disadvantageous that a key is needed, which is associated with high costs, in order to prevent co-rotation of the tie rod.

Also, the converse variant of a screw connection is known in the prior art. Here, the diaphragm assembly does not have a threaded extension, instead the threaded extension is provided by the tie rod. However, this known embodiment does not overcome the explained disadvantages of the screw connection formed by the diaphragm assembly. Instead, recourse must be had to a special tool in order to screw the diaphragm assembly onto the threaded extension.

Alternatively, it is known from the prior art that the diaphragm layers can be held directly by the diaphragm disc and the tie rod without the diaphragm assembly comprising a clamping screw. The tie rod also fulfils the function of the clamping screw. This solution leads to the situation where either the tie rod also has to be replaced when the diaphragm is changed or the diaphragm assembly must be preloaded correctly on site, bonded and provided with separating means.

This third embodiment known from the prior art is also associated with disadvantages, in particular replacing the diaphragm assembly is not possible without simultaneous replacement of the tie rod if the diaphragm assembly is not produced again, amongst other things by preloading and bonding on site.

The object of the present invention is therefore to overcome the disadvantages of the prior art and, in particular, to provide a secure connection of diaphragm assembly and tie rod which can be carried out without complicated assembly, wherein in particular the risk of damage to the diaphragm during the assembly is minimized.

This object is achieved by a diaphragm pump having a diaphragm assembly and a diaphragm return device comprising a tie rod, wherein the diaphragm assembly comprises a diaphragm and a diaphragm stop device fixing the diaphragm, wherein the diaphragm assembly and the tie rod are connected to each other with a force fit by means of a magnetic adhesive force.

It may be especially advantageous that the magnetic adhesive force is greater than or equal to the maximum required return force of the diaphragm during the operation of the diaphragm pump,

The invention is based on the surprising finding that a force-fitting connection of tie rod and diaphragm assembly can be provided by means of a magnet, it being possible to dispense with the screw connections known from the prior art. The magnet itself must be dimensioned such that a permanent force-fitting connection is ensured in all desired operating situations. This means in particular that the magnetic adhesive force provided between diaphragm assembly and tie rod is greater than the maximum required return force of the diaphragm during the operation of the diaphragm pump.

It has transpired that the maximum required return force usually lies in a range from 50 N to 2400 N, in particular in a range from 100 N to 1200 N. Such magnetic adhesive forces can easily be reached with the given geometries by means of modern permanent magnets, for example neodymium magnets.

It is particularly advantageous that assembly of the diaphragm or the diaphragm assembly can be carried out without tools. Consequently, slipping of the same can be avoided, and thus damage to the diaphragm is minimized. In addition, the magnetic connection is wear-free and secure against breakage. Breakage of the thread used according to the prior art as a result of excessively high tightening is no longer possible.

Furthermore, the present invention is associated with further advantages since, for example, magnetic particles are caught by the magnet. Such particles can arise, for example, during the operation of the diaphragm pump, as a result of wear particles from the piston rings, liberated machining residues and other abrasion. Damage to the diaphragm by wear particles is additionally effectively prevented.

It is also possible to dispense with the complicated construction of the key, so that considerable savings in costs arise, which more than compensate for the use of the more expensive magnets.

According to the invention, various embodiments of arrangements of one or more magnets are conceivable in order to provide the aforesaid adhesive force. The magnet or the magnets can, according to the invention, be comprised by the diaphragm assembly and/or by the tie rod or arranged detached from the latter.

According to the invention, provision can be made for the diaphragm stop device to comprise a diaphragm stop disc and a diaphragm stop element connected to the diaphragm stop disc, the diaphragm being arranged between the diaphragm stop disc and the diaphragm stop element.

A diaphragm assembly generally comprises, as explained, a diaphragm having two PTFE layers and a woven layer arranged between these layers. To fix these three layers, a diaphragm stop disc is arranged on one side of the diaphragm, and a diaphragm stop element, generally in the form of a clamping screw, is arranged on the opposite side.

As a result of connecting the diaphragm stop disc and diaphragm stop element, the diaphragm is fixed and can be connected to the tie rod of the diaphragm return device. According to one embodiment of the present invention, a first magnet for providing the magnetic adhesive force is arranged on or in the area of the end of the tie rod that faces the diaphragm.

It has transpired that an arrangement of a first magnet on the side of the tie rod that faces the diaphragm or the diaphragm assembly is particularly advantageous for providing the adhesive force according to the invention, since the distance between the elements to be connected can be minimized. Optionally, the surface of the tie rod has a recess, into which the first magnet is fitted. Further optionally, the magnet is connected to the tie rod surface by suitable adhesive means or adhesive.

According to this embodiment, the first magnet remains on the tie rod in the event that the diaphragm assembly is changed. However, this arrangement of the first magnet assumes that the diaphragm assembly, in particular the diaphragm stop element, has sufficient magnetic properties to be able to interact with the first magnet for the necessary adhesive force.

Therefore, according to a further embodiment, provision can also be made for a second magnet for providing the magnetic adhesive force to be arranged on or in the area of the diaphragm stop element. Optionally, the surface of the diaphragm stop element has a recess, into which the second magnet is fitted. Further optionally, the magnet is connected to the surface of the diaphragm stop element by suitable adhesive means or adhesive.

Here, too, the distance between the elements to be connected, tie rod and diaphragm assembly, is minimized. This can primarily be advantageous when the magnetic properties of the diaphragm assembly used are not sufficient.

Alternatively, according to an embodiment of the invention, provision can likewise be made for the first magnet to be arranged on or in the area of the end of the tie rod that faces the diaphragm, and for the second magnet to be arranged with reverse polarity opposite the first magnet in the area of the membrane stop element, the first magnet, together with the second magnet, providing the magnetic adhesive force.

This arrangement according to the invention is particularly advantageous for generating a high adhesive force. In addition, the adhesive force is adjustable independently of the geometry and the materials of the diaphragm assembly and the tie rod.

Alternatively, according to a further embodiment of the present invention, provision can be made for a third magnet for providing the magnetic adhesive force to be arranged in the area of the diaphragm stop element and/or in the area of the end of the tie rod that faces the diaphragm, but not to be connected to the diaphragm stop element and/or the tie rod.

It may be advantageous, but does not have to be, if the magnet or the magnets is or are connected directly to the tie rod or the diaphragm assembly. Provision is likewise made for the magnetic adhesive force to be provided by a third magnet present separately therefrom.

According to one embodiment of the present invention, it may be preferred for the diaphragm stop element to have a recess, into which the tie rod and/or the first magnet connected to the tie rod is inserted, so that the diaphragm assembly is centred with respect to the tie rod. According to a further embodiment, the depth of the recess of the diaphragm stop element is greater than the height of that part of the tie rod and/or of the first magnet connected to the tie rod which is inserted into the recess.

According to the solutions from the prior art, centring of the diaphragm assembly with respect to the tie rod was carried out during the connection of the same to the threaded extensions of the screw connections used. By means of the magnetic connection according to the invention, it may be advantageous if an alternative centring support of the diaphragm assembly with respect to the tie rod is possible. Such centring can be carried out by the recess according to the invention, so that the tie rod or the first magnet that is connected to the tie rod is partly introduced into the recess provided for this purpose in the diaphragm stop element and is thus centred.

According to the invention, provision can be made for the recess to be at least partly rectangular, trapezoidal, conical, cylindrical or semi-cylindrical in its cross section.

The configuration of the recess is obviously not restricted for those skilled in the art. However, the geometries listed have proven to be particularly advantageous.

According to the invention, provision can be made for the magnet or the magnets to be formed in the shape of a disc magnet, a conical magnet, a spherical magnet and/or a ring magnet.

Depending on the magnetic adhesive force, different magnet shapes may be advantageous and implemented. The following should be mentioned by way of example: magnets in the form of a disc, rod, cube, die, sphere, ring or cone. It has transpired that the use of magnets in the form of a die, cone, sphere and ring is particularly advantageous.

Provision can also be made for the magnet or magnets to be formed as (a) permanent magnet(s) or as (an) electromagnet(s).

Important to the invention is the use of magnets for producing a force-fitting connection between the diaphragm assembly and tie rods. Depending on the application, permanent magnets or electromagnets can be used, the first being particularly advantageous in a connection to the diaphragm assembly, while electromagnets can be implemented particularly advantageously in combination with the tie rod because of the necessary electrical contacts.

Furthermore, provision can be made for the magnet or the magnets to have a corrosion-resistant coating.

To be protected as well as possible for the respective environmental conditions, depending on the area of use of the diaphragm pump, it may be advantageous for the magnet or the magnets to comprise a corrosion-resistant coating. The type of coating depends directly on the area of use of the pump and can be selected accordingly in a known way by those skilled in the art.

Finally, provision can also be made for the magnet or the magnets to comprise a thread, a recess and/or a projection, designed and configured in particular to simplify detachment of the connection between the magnet and tie rod and/or diaphragm stop element.

Further features and advantages of the invention can be gathered from the following description, in which exemplary embodiments of the invention will be explained by way of example by using schematic drawings without restricting the invention as a result.

FIG. 1 illustrates a detail of an embodiment of a diaphragm pump 1 according to the invention in a sectional view. The diaphragm pump 1 comprises a diaphragm 3, which comprises two PTFE layers 5, 5′ and a fabric layer 7 arranged between these. To fix these three layers 5, 5′, 7 and to form a diaphragm assembly 9, a diaphragm stop disc 11 is arranged on one side of the diaphragm 3, and a diaphragm stop element 13, here in the form of a clamping screw, is arranged on the opposite side.

A permanent magnet 15 provides a magnetic adhesive force between the diaphragm assembly 9 and a tie rod 17 of a diaphragm return device 19, so that the diaphragm assembly 9 and the tie rod 17 are connected to each other with a force fit by means of the magnetic adhesive force. The tie rod co-operates with a spring 21 in order to provide the required return force and to move the diaphragm into the suction stroke position. The diaphragm stop element 13 has a recess 25 for the insertion of the magnet. The magnet 15 is firmly connected to a head 23 of the tie rod 17 that faces the diaphragm assembly 9, so that the diaphragm assembly is centred with respect to the tie rod.

A further embodiment of the present invention with centring support is shown in FIG. 2. Here, the diaphragm stop element 13 has a hemispherical recess 25′, into which the area of the spherical magnet 15′ which is fixed to the tie rod 17 and which projects beyond the diaphragm stop element 13 can be inserted. In this position, the diaphragm assembly 9 is centred with respect to the tie rod 17. The recess 25′ can also be trapezoidal, as shown in FIG. 3. It is advantageous if the recess 25, 25′ or 25″ corresponds to the shape of the magnet 15, 15′ or 15″.

A further embodiment of the present invention with centring support is shown in FIG. 4. Here, the depth of the recess of the diaphragm stop element is greater than the height of that part of the first magnet which is connected to the tie rod and which is inserted into the recess.

It is obvious that different magnet shapes 15 and configurations of the recesses 25 may be advantageous, variants from the present invention that are not shown also being comprised.

In the foregoing discussion and in the claims that follow, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” The phrase “consisting essentially of” means that the described/claimed composition does not include any other components that will materially alter its properties by any more than 5% of that property, and in any case does not include any other component to a level greater than 3 mass %. The term “or” is intended to encompass both exclusive and inclusive cases, i.e., “A or B” is intended to be synonymous with “at least one of A and B,” unless otherwise expressly specified herein. The indefinite articles “a” and “an” refer to both singular forms (i.e., “one”) and plural referents (i.e., one or more) unless the context clearly dictates otherwise.

The features of the invention disclosed in the above description, the claims and the drawings can be important both on their own and also in any desired combination for the implementation of the invention in its various embodiments. 

1. A diaphragm pump, comprising: a diaphragm assembly comprising a diaphragm and a diaphragm stop device fixing the diaphragm, and a diaphragm return device comprising a tie rod, wherein the diaphragm assembly and the tie rod are connected to each other with a magnetic adhesive force, and wherein a first magnet for providing the magnetic adhesive force is arranged on or in the area of the tie rod, and wherein the diaphragm stop device has a recess, into which the tie rod and/or the first magnet connected to the tie rod is inserted, so that the diaphragm assembly is centred with respect to the tie rod.
 2. The diaphragm pump of claim 1, wherein the magnetic adhesive force is greater than or equal to the maximum required return force of the diaphragm during the operation of the diaphragm pump.
 3. The diaphragm pump of claim 1, wherein the diaphragm stop device comprises a diaphragm stop disc and a diaphragm stop element connected to the diaphragm stop disc, the diaphragm being arranged between the diaphragm stop disc and the diaphragm stop element.
 4. The diaphragm pump of claim 1, further comprising a second magnet for providing the magnetic adhesive force, the second magnet being arranged on or in the area of the diaphragm stop element.
 5. The diaphragm pump of claim 4, wherein the first magnet is arranged on or in the area of the end of the tie rod that faces the diaphragm, and the second magnet is arranged with reversed polarity opposite the first magnet in the area of the diaphragm stop element, wherein the first magnet together with the second magnet provides the magnetic adhesive force.
 6. The diaphragm pump of claim 1, further comprising a third magnet for providing the magnetic adhesive force is arranged in the area of the diaphragm stop element or in the area of the end of the tie rod that faces the diaphragm but is not connected to the diaphragm stop element or the tie rod.
 7. The diaphragm pump of claim 4, wherein the tie rod has a recess, into which the diaphragm stop element or the second magnet that is connected to the diaphragm assembly is inserted.
 8. The diaphragm pump of claim 1, wherein the recess is at least partly rectangular, trapezoidal or semi-cylindrical in its cross section.
 9. The diaphragm pump of claim 1, wherein the first magnet is formed in the shape of a disc magnet, a conical magnet, a spherical magnet or a ring magnet.
 10. The diaphragm pump of claim 1, wherein the first magnet is a permanent magnet or an electromagnet.
 11. The diaphragm pump of claim 1, wherein the first magnet has a corrosion-resistant coating.
 12. The diaphragm pump of claim 1, wherein the first magnet comprises a thread, a recess or a projection that is designed and configured to detach the connection between the first magnet and the tie rod or the first magnet and the diaphragm stop element.
 13. The diaphragm pump of claim 1, wherein the first magnet is connected to the surface of the tie rod or the surface of the diaphragm stop element using an adhesive.
 14. The diaphragm pump of claim 1, wherein the depth of the recess of the diaphragm stop element is greater than the height of that part of the tie rod or the first magnet that is connected to the tie rod when inserted into the recess.
 15. A pump, comprising: a diaphragm assembly comprising a diaphragm and a diaphragm stop device fixing the diaphragm, and a diaphragm return device comprising a tie rod, wherein the diaphragm assembly and the tie rod are connected to each other with a magnetic adhesive force, a first magnet for providing at least a portion of the magnetic adhesive force, the first magnet arranged on or in the area of the tie rod, a second magnet for providing at least a portion of the magnetic adhesive force, the second magnet being arranged on or in the area of the diaphragm stop element; and a third magnet for providing at least a portion of the magnetic adhesive force, the third magnet arranged in the area of the diaphragm stop element or in the area of an end of the tie rod that faces the diaphragm but is not connected to the diaphragm stop element or the tie rod, wherein the diaphragm stop device has a recess, into which the tie rod and/or the first magnet connected to the tie rod is inserted, so that the diaphragm assembly is centred with respect to the tie rod.
 16. The pump of claim 15, wherein each magnet is formed in the shape of a disc magnet, a conical magnet, a spherical magnet or a ring magnet.
 17. The pump of claim 15, wherein each magnet is as a permanent magnet or an electromagnet.
 18. The pump of claim 15, wherein at least one of the magnets has a corrosion-resistant coating. 